Portable power-driven screw driver



April 24, 1945. E. s MOORE PORTABLE POWER DRIVEN SCREW DRIVER Filed July 5, 1943 4 in alinement with the casing 3.

Patented Apr. 24, 1945 2,374,558 PORTABLE POWER-DRIVEN SCREW DRIVER Edgar S. Moore, Toronto, Ontario, Canada Application July 5, 1943, Serial No. 493,629

12 Claims.

This invention relates to screw driving apparatus of the portable power driven type and one object of my invention is to devise a comparatively simple construction by means of which a plurality of screws are automatically fed one at a time to the driving position, each screw being advanced by manual pressure while it is rotated by power driven means. A further and important object is to devise such a construction in which the driving of the screw will automatically cease when it is driven home to the desired extent independently of the length of the screw, so that the top of thehead of each screw will occupy the same position relative to the surface of the material into which the screws are driven.

I attain these, as well as other objects, by means of the construction hereinafter described and illustrated in the accompanying drawing in which:

Fig. 1 is a front elevation, partly in section of the improved screw driver;

In the drawing like numerals of reference in- I dicate corresponding parts in the different figures.

l indicates a screw driving spindle which is mounted not only to slide longitudinally of a housing, but is also rotatable therein. The housing comprises an intermediate gear box 2, an upper tubular casing 3 and a lower tubular casing provided with an enlargement 5 at its lower end, the lower end of which spindle is shaped to engage for turning purposes the head of a screw. In the present case the screw is shown with the usual transverse groove and the end of the enlargement is therefore formed with a transverse rib.

The upper end of the spindle is provided with a head 1, and interposed between the under side of the head and the top of the gear box is a coil spring fl which tends to hold the spindle in raised or retracted position.

The screw driving spindle is shown as driven from the shaft 9 of an electric motor H], by means of a train of gears. I l journalled in the gear box 2. The spindle I is slidable'through the last gear I I in the train, but is keyed thereto in order that rotation of the gears simultaneously efiects the rotation of the spindle l.

The spindle is trio motor, it will be evident that any other form of power supply, such as for example. a compressed air operated means may be substituted for the motor.

It will be seen therefore that while the motor or other power device is operating, the spindle I is being continuously rotated.

As stated above, the spring 8 normally holds the spindle retracted out of screw-engaging positracted position by a spring. 93 interposed on the stem between the head l2 and the end of the casing 3. A pin M extending from the stem 2| into a slot 15 holds the stem 2| from rotation.

Secured to andprojecting from the under side of the head or handle I2 is an arm Hi, to which is pivotally connected one end of a lever H, which has pivotally connected with one side of its other end a cam member l8.

In Figs. 1 and a, this cam member is shown positioned inthe interior of the casing 3 between the head i of the spindle l and the lower end of the stem H of the handle l2, whilethe end of the lever l! is positioned outside the casing, a pivot pin l8 extending through a vertical slot 20 in the side of said casing 3. An exit opening 22 is formed through the side of the. casing 3 at the bottom of the slot 20, while an inlet opening 23 is formed through the same side of the casing at the upper end of the slot 20.

By pushing down on the handle l2 against the pressure of the spring l3, the lever or push rod I"! causes the cam I8 to move downwardly in the casing 3, where it. engages the head 1 of the spindle l, and forces the latter downwardly to engage and drive the screw into place. When the cam reaches the bottom of the slot, and is therefore in alinement with the exit 22, the cam moves outwardly through said outlet, this outward movement being facilitated by the inclination of the lever or push rod ll relative to the axisof the spindle I, and handle stem 2|. It will be seen therefore that the driving of the screw is limited by the length of the slot 2!], and as soon as thercam escapes. pressure upon the handle I2 is released, and the spring {3 moves the handle upwardly dragging the lever I1 and connected cam 18 with it, said cam travelling up the outside of the casing 3 until the inlet opening 23 While I show the gearing as driven by an elecis reached, the inclination of said lever causing the cam to enter the opening at the proper time to position it above the head 1 ready for the next cycleof operations.

In Fig. 6 the cam member I8 is shown near the top of its upward movement ready to enter the upper opening 23 under the drag of the lever IT. The lever 32 when in its upper position, helps to guide the cam in member I! into this opening 23.

It will be seen, therefore, that as the amount of travel of the spindle is limited to the same extent in each operation, the extent to which the screw is driven is also regulated, so that they are all driven to the same uniform depth.

It is desirable that the screws be fed automatically one after the other into position for driving, and I therefore provide the following mechanism for this purpose. Secured to one end of the gear box 2 is a magazine housing 24 in which are journalled two spaced rolls 25 and 26, over which passes an endless belt 2'l,'from the front of which project partitions 28, which partitions, the belt 21 and the inside of the housing 24 cooperate to form a series of compartments 29 in each of which a screw may be inserted.

The belt 21 has on its back a series of ribs or shoulders 30, one for each compartment and the belt is advanced step by step by means of a spring held ratchet 3| mounted on a lever arm 32, pivoted on a, lug'33 on the inside of the housing 24. The free end of this lever arm projects through the side of the housing 24 nearest the casing 3 and normally lies in the path of the cam l8 as it travels upwardly outside the casing 3. It will be seen, therefore, that the lever arm 32 is actuated by the cam to effect the feeding of another screw directly afterthe completion of driving of a screw.

The housing 24 is provided'with an opening in its bottom through which screws may fall one by one as the various screw compartments pass over the delivery point. Communicating with this opening is a chute or guide-way 34, which communicates with the interior of the casing 4 as shown in Fig. 1.

To ensure that screws drop into the guideway and therefore slide into the casing 4 with the point in proper driving position, that is, lowermost, a shoulder 35' is formed at the upper end of the guide, with which shoulder the head of the screw engages temporarily to give the point time to swing downwardly, as indicated in dotted lines in Fig. 1, after which the screw as a whole slides into position for driving.

The magazine housing 24 is provided with an inlet opening 38 at its upper end, through which screws may be fed one by one from any suitable means (not shown).

It will be evident, of course, that toothed sprocket gears, and sprocket chain may be substituted for the rolls 25 and- 26 and belt 21, and the separators or carriers being mounted on the back'of the chain.

The device is provided with a suitable hand grip 36 for manipulation purposes, which I show as formed on the motor housing. One hand is engaged with this grip 36, while the other hand engages the handle l2.

A leg 31 extends downwardly from the gear box 2, so that by engaging the lower end of the housing t and the leg 31 on the work, the device will be held to drive the screws into the work in are fingers 39. These fingers are formed of spring metal, but tend normally to remain out of screw engaging position as shown in dotted lines. They are, however, forced into centering position by lever 40 having a forked end, one arm extending each finger. The lever All is pivoted intermediate its ends on a stationary part, such as a bracket 4! extending from the leg 37. The lever is provided with a work-engaging extension 40 and the lever is spring loaded so that it normally projects beyond the foot of the leg 31 as indicated, with the forked end engaging the fingers 39 and holding them in centering position. The screw, it will be noted, projects sumciently beyond the end of the casing 5, so that its end may be located in the proper position on the work. The leg is then engaged with the work, thus causing the lever 40 to rock and disengage the forked end from the fingers, allowing them to move outwardly to clear the way for the driving spindle. After the screw is driven home, the apparatus is lifted from the work for movement to a fresh position, and the lever to is then actuated by its spring to move the fingers 39 into centering position for the next screw.

What I claim as my invention is:

1. In a portable power driven tool, the combination of a hollow body; a spindle rotatable in said body, and also slidable axiallybetween ex tended and retracted positions, yielding means normally urging said spindle to retracted position; means for rotating said spindle; said body having a slot formed longitudinally of one side thereof, a cam outlet at one end of the slot, and a cam inlet at the other end of the slot; and means for moving said spindle to extended position comprising an operating handle; a push rod having one end pivotally connected-with the ham dle, a pin extending from the side of said push rod adjacent its other end through said slot into the interior of the body, and a cam member on normally urging said spindle to retracted position; means for rotating said spindle; said body having a slot formed longitudinally of one side thereof, a cam outlet at one end of the slot and a cam inlet at the other end of the slot; and means for moving said spindle to extended position comprising an operating handle; a push rod having one end pivotally connected with the handle, a pin extending from the side of said push rod adjacent its other end throughsaid slot into the interior of the body, and a cam member on said pin; said push rod being arranged at an angle to the axis of the spindle.

3. In a portable power driven tool, the combi-; nation of a hollow body; a spindle rotatable in said body and also slidable axially between extended and retracted positiona'yielding means normally urgingsaid spindle to retracted position; means for rotating said spindle; said body having a slot formed longitudinally of one side thereof, a cam outlet at one end of'the slot'and a cam inlet at the other end of the slot; and means for moving said spindle to extended position comprising an operating handle; a push rod having one end pivotally connected with the handie, a pin extending from the side of said push rod adjacent its other end through said slot into the interior of the body, and a cam member on said pin and yielding means normally tending to.

thereof, a cam outlet at one end of the slot and a cam inletat the other end of the slot; and

,means for moving said spindle to extended position comprising an operating handle having a stem slidable in the upper end of the body; yielding means normally tending to move the handle away fromthe body; a pushrod having one end pivotally connected with the handle, a pink extending from the side of said push rod adjac'ent its other end through said slot into the interior of the body, and'a cam member on said pin.

5. In a portable power driven tool, the combination of a hollow body, a spindle rotatable in said body and also slidable axially between extendedand retracted positions, yielding means normally urging said spindle to retracted position; means forrotating said spindle; said body having a slot formed longitudinally of one side thereof, a cam outlet at one end of theslot and a cam inlet at the other end of the slot; and means for moving said Spindle to extended position comprising an operating handle having a stem slidable in the upper. end of the body; yielding means normally tending to move the handle away from the body; a push rod having one end pivotally connected with the handle, a pin ex tending from the side of said push rod adjacent its other end through-said slot into the interior bination of a hollow body; a spindle rotatable in said body and also slidable axially between extended and retracted positions, yielding means normally urging said spindle to retracted position; means for rotating said spindle; said body having a slot formed longitudinally of one side thereof, a cam outlet at one end of the slot and a cam inlet at the other end of the slot; and means for moving said spindle to extended position comprising an operating handle; a push rod having one end pivotally connected with the handle, a pin extending from the side of said push rod adjacent its other end through said slot into the interior of the body, and a cam member on said pin; and means for automatically feeding screws to said body below the spindle, said means including an operating member positioned to be actuated by said cam on its upward travel.

'7. In a portable power driven tool, the combination of a body; a spindle rotatable in said body and also slidable axially between extended and retracted positions, yielding means normally urging asid spindle to retracted position; means for rotating said spindle; means for moving said spindle to extended position; and means for antomatically feeding screws to said body below the spindle comprising a magazine housing; spaced rollers journalled in said housing; an endless carrier mounted on said rollers, partitions carried by said carrier forming with the inner wall of the housing a series of screw compartments, said housing having a discharge opening at its lower end communicating with the body below the spindle; and means actuated by the spindle extending means for'actuating said carrierto position said compartments one by one o-verthe discharge opening. 8. In a portable power driven tool, the combi nation of a body;a spindle rotatable in said body and alsoslidable axially between extended and. retracted positions, yielding means normally urg ing said spindle to retracted position; means for rotating said spindle; means for movingsaidspindle to extended position; and means for automatically feeding screws to said body below the spindlecomprising a magazine housing; spaced rollers journalled in said housing; an endless carrier mounted on said rollers, partitions carried by said carrier forming with the inner wall of the housing a series of screw compartments; said housing having a discharge opening at its lower end communicating with the body below the spindle; said carrier having a series of shoulders on its surface; and means actuated by the spindle extending means for engaging said shoulders to actuate the carrier to position said compartments one by one over the discharge opening.

9. In a portable power driven tool, the combination of a body; a spindle rotatable in said body and also slidable axially between extended and retracted positions, yielding means normally urging said spindle to retracted position; means for rotating said spindle; means for moving said spindle to extended position; and means for automatically feeding screws to said body below the spindle comprising a magazine housing; spaced rollers journalled in said housing; an endless carrier mounted on said rollers, partitions carried by said carrier forming with the inner wall of the housing a series of screw compartments, said housing having a discharge opening at its lower end communicating with the body below the spindle; said housing having a shoulder at one end of said opening with which the head of a screw temporarily engages while the point of the screw is dropping through the opening; and means actuated by the spindle extending means for actuating said carrier to position said compartments one by one over the discharge.

10. In a portable power driven tool, the combination of a hollow body; a spindle rotatable in said body and also slidable axially betw'een ex tended and retracted positions, yielding means normally urging said spindle to retracted position; means for rotating said spindle; said body having a slot formed longitudinally of one side thereof, a cam outlet at one end of the slot and a cam inlet at the other end of the slot; and means for moving said spindle to extended position comprising an operating handle; a push rod having one end pivotally connected with the handle, a pin extending from the side of said push rod adjacent its other end through said slot into the interior of the body, and a cam member on said pin; means for automatically feeding screws to said body below the spindle comprising a magazine housing; spaced rollers journalled in said housing; an endless carrier mounted on said rollers, partitions carried by said carrier forming with the inner wall of the housing a series of screw compartments, said housing having a discharge opening at itslower end communicating with the body below the spindle; and means actuated by the cam for actuating said carrier to position said compartments one by one over the discharge opening.

11. In a portable power driven tool, the combination of a hollow body; a spindle rotatable in said body and also slidable axially between extended and retracted positions, yielding means normally urging said spindle to retracted position, means for rotating said spindle; said body having a slot formed longitudinally of one side thereof, a cam outlet at one end of the slot and a cam inlet at the other end of the slot; and means for moving said spindle to extended, position comprising an operating handle; a push rod having one end pivotally connected with the handle, a pin extending from the side of said push rod adjacent its other end through said slot into the interior of the body, and a cam member on said pin; means for automatically feeding screws to said body below the spindle comprising a magazine housing;

spaced rollers journalled in said housing; an endless carrier mounted on said rollers, partitions carried by said carrier forming with the inner wall of the housing a series of screw compartments; said housing having a shoulder at one end of said opening with which the head of a screw temporarily engages While the point of th screw is dropping through the opening.

12. In a portable power driven tool, the'eoinbination of a hollow body; a spindle rotatablein said body and also slidable axially between ex: tended and retracted positions, yielding means normally urging said spindle to retractedposition; means for rotating said spindle; said body having a slot formed longitudinally of one side thereof, a cam outlet at one end of the slot and a cam inlet at the other end of the slot; and means for moving said spindle to extended position com- 

